Quote:
Originally Posted by Homeoboxter
However, I think both solenoids and actuators are working, because what happens is fairly similar between both banks. So, somehow, they are synchronously bad. Perhaps there's a broken wire somewhere which somehow affects both actuators.
For cam angle values over 20 the values clearly separate, which probably means one bank is not able to move the timing to the target range, probably because the chain pad is shot on that side.
Can you arrange the dataset in a time dependent manner?
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Like this?
I think I see that you're saying.
1) They are clearly separated at the 20+ degree step. I'm guessing that it's the intake cam being advanced.
2) Also, it also doesn't look like they are moving together when they shift from the nominal 0 level the 20 degree+ level. This may be a time phasing issue since I wasn't taking a gazillion data points. It looks like the logger was capturing a data point every ~1.3 seconds.
But it looks like it's definitely the ramps.
I guess my project is now to replace them and run another set of data to confirm the solution.
Quote:
Originally Posted by Homeoboxter
Something seems off, because the actuator shifts at 2500 rpm and 5500 if i remember correctly, so all your data points below 2500 and above 5500 should fall around zero, while the data points between 2500 and 5500 should be around 23-24. That's clearly not the case.
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Good point. It seems like the variocam is kicking in about 1000 RPM too low, and turning off about 500 RPM too low. Doing a web search, it looks like the actuation of the variocam is dependant on RPM
and load. At lower engine loads, the actuation of the variocam is retarded. Under higher load (such as an entrance ramp engine pull) the actuation is advanced. Initially when accelerating from my driveway and a nearby stop sign, the load was high. Than I was cruising on a 2ndary road with 1 stop-light, in ~3rd gear, so no variocam was activated because the load on the engine was light.
It definitely seems like bank 2 is not advancing as much as bank 1. I guess the variocam system advances the intake cam by 13 cam degrees (or 26 crank degrees. I'm guessing the system measures everything in crank degrees). So the bank 1 intake cam appears to have lost about 1 degrees of advance, while bank 2 seems to have lost about 2 degrees of advance. So maybe bank 2 is the real problem(?). Or is it that both sides are retarded (i.e. 1/4-1/2 degree of wear on the tensioner ramps for the long chains, or the chains themselves), in addition to 1-2 degrees of wear on the variocam ramps?
Either way, I'm going to replace the variocam ramps on both sides while I'm under the car.